Method of forming wheel-disks



I A ICHRISTI'ANSONJ METHOD oaonmme WHEEL msKs.

APPLICATION HLED JULYZIQIQQOLI Patented Dec. 6, 1921.

2 SHEETS-SHEET 1.

FIEJL- I FIE-E- IN VENTO R WITNESSES A. CHRISTIANSON.

METHOD OF FORMING WHEEL DISKS.

APPLICATION FILED JULY 21, 1920.

' Patented Dec. 6, 1921.

2 SHEETS-SHEET 2.

INVENTOR PATENT OFFICE.

ARNOLD CHRISTIAN SON,

OF DETROIT, MICHIGAN.

METHOD OF FORMING- WHEEL-DISKS.

Application filed July 21,

T0 call whom it may concern Be it known that I, ARNOLD CHRISTIAN- SON, a resident of Detroit, in the county of Wayne and State of Michigan, have invented a new and useful Improvement in Methods of Forming Wheel-Disks, of which the following is a specification.

The invention relates to a method of forming metal disks from blanks of substantially uniform thickness, with the thickness of the finished diskgradually tapering from near its center to its periphery. The object is to provide a method of making such disks without buckling the metal, or producing radial cracks, or strains tending to produce radial cracks, and also without waving or buckling the metal.

One use of disks of the character specified is to form the web portion of vehicle wheels, such as'used on motor cars, and in which, for the sake of lightness coupled with proper strength, it is necessary that the thickness of the disk decrease from the central portion uniformly and progressively to the periphery thereof.

Prior methods for producing such disks have involved the working of the blank either by dies or by rollers so as to increase the diameter of the blank, that is, cause the metal to flow radially with reference to the disk. This method is liable to produce radial cracks at the periphery of the disk, or strains which are likely to develop into radial cracks. Efforts have also been made to roll fiat blanks by rolls whose axes are substantially radial to the circular blanks, but since when such rolling action is applied to a fiat blank the metal must flow circumferentially, it has produced wavy. disks, for reasons which are apparent.

The present method overcomes the foregoing difi'iculties and enables the production of circular disks uniformly tapering from near their centers to their peripheries in such a manner that the cross sectional area of the metal or any circle outside of the central zone is equal to that of any other circle, and without causing the metal to wave or buckle and without liability of producing radial cracks, or strains which tend to produce such cracks.

Generally stated the invention consists in first shaping a circular plate to cup form, preferably by a punch anddie drawing operation, and preferably to substantially cy mdncal shape, and then subjecting the Specification of Letters Patent.

Patented Dec. 6, 1921.

1920. Serial No. 397,958.

walls of the cup to a rolling action so applied as to produce the greatest reduction in thickness of the cup walls (and consequently the greatest circumferential expansion thereof) at the open end of the cup, and gradually and uniformly decreased toward the bottom of the cup, whereby the cupshaped blank is caused to flare, and continuing such action and increasing the fiare of the blank until formed into a substantially fiat disk of the character above described.

The improved method may be carried out by various forms of apparatus. The apparatus for producing the cupping of the blank may, and preferably will be of the well known punch and die type, while the means for applying the rolling action to convert such cup-shaped'blank into a substantially flat disk may be of various forms and constructions, such for instance as shown in either of my applications of even date herewith, Serial Nos. 397,956 and 397,957.

In the accompanying drawingsFigure 1 represents the initial blank; Fig. 2 represents the blank after the first cupping operation; Fig. 3 represents the blank after the final cupping operation; Fig. 4 is a plan view illustrating one form of rolling mecha-' nism for converting the cup-shaped blank into a disk, showing the cup-shaped blank at the beginning of the rolling operation; Fig. 5 is an enlarged diagrammatic view illustrating the rolling action at an intermediate stage; and Fig. 6 is a .diametrical sectional view of the finished blank.

In the practice of the method a circular blank 1, such as shown in Fig. l is formed in any suitable way, such as by cutting from a sheet or plate of steel of the required thickness. The size of this blank will depend upon the diameter of the desired finished disk, but in allcases will be of less diameter than the finished disk. This blank is then heated and subjected to a cupping operation, such as by the well known. method of forcing the blank by means of a punch through a suitable die. This cupping operatlon will be carried out in stages, in a manner well known, the first punch and die forming the same into. a shallow cup, such as shown at 2 inFig. 2, and the succeeding punches and dies being of gradually decreasing dlameters and successively forming the blank into a cup of progressively increasing depth and decreasing diameter, the final shape of the cup preferably being that shown at 3 in Fig. 3, namely, a cup of relatively small diameter and considerable depth. Drawing punches and dies of the character described, as is well known, produce a cup having walls of uniform thickness, and in which the metal of the walls of the cup is caused to flow in a direction longitudinal to the axis of the cup, or radially to the original blank, the metal forming the bottom of the cup remaining substantially of its original thickness. The bottom of the cup is provided with a central hole 5 which may be punched either in the original blank or in the cup at any stage during its formation.

The cupping action is continued until the depth of the cup plus one-half of its diameter is substantially equal to one-half the diameter of the desired finished disk. This dimension, however, is greater than onehalf the diameter of the original blank; due to the .fact that in cupping the blank the metal, which would otherwise tend to form into folds toward the open end of the cup, is caused to flow longitudinally by the drawing operation, as will be readily understood.

The cup is then subjected to a rolling action to reduce the thickness of its walls and to expand the circumference of the same, and so applied as to produce the greatest reduction in thickness and expansion in circumference at the open end and gradually and uniformly decreasing toward the bottom of the cup, where the expansion and reduction are zero. In other words, the cup is caused to flare, and the flaring action is continued until the walls of the cup are substantially in the same plane as its bottom. This action can be produced by a variety of rolling means. To show one way in which this can be done there is illustrated in Fig. 4 a form of rolling apparatus substantially such as illustrated in my application Serial No. 397,956, above referred to. This apparatus comprises a pair of rolls 6 and 7, one of which enters the cup from its open end and bears against the inner face of the walls thereof, while the other bears on the outer face thereof, thus forming a reducing pass therebetween. These rolls preferably are of conical shape as shown, so as to produce the greatest reducing and expanding action at the open end of the cupshaped blank and gradually decreasing toward the bottom thereof where it is zero. In addition, the axes of the rolls are set at such position, while means areprovided for changing the angular position of the axes of one of the rolls, so as to progressively and continuously decrease the width of the pass at the open end of the cup, as the reduction and expansion progresses. To this end the shaft of one of the rolls, such as the roll 6,

is mounted in stationary bearings 8 and that of the other roll 7 is mounted in bearings 9 on a carrier 10, pivoted at 11 and movable by suitable means, such as the screw 12 and hand wheel 13, whereby as the reduction progresses the space between the conical rolls at the open end of the cup-shaped blank is progressively decreased, while the space between the inner ends of the rolls, at the bottom of the cup, remains substantially constant, all as described in my application Serial No. 397,956. To hold the cup in position between the rolls itsbottom is engaged by a disk ll having a spindle l5 rotatably mounted in a bearing 16 on a carrier 17, which is also pivotally mounted at the center 11, in such mannerthat' it will automatically shift its angular position relative to the axis of the roll pass, as also fully described in my application, Serial No. 397,956. The reduction produced by these rolls is graphically shown in Fig. 5, which shows in full lines 19 the position of the parts shortly after the beginning of the roll ing operation. in which the cup-shaped blank is only slightly flared at its open end and the retainer 16 hasassumed a slight angular position, by the dotted lines 20 the flare of the cup at a later stage of reduction and expansion. with the retainer 16 at a greater angular position, and by the dotted lines :21 the tinal position in which the cupshaped blank has been converted into a substantially fiat blank with the retainer-16 with its axis substantially at right angles to its original position. During this action the axis of the movable roll has been gradually and progressively changed, as above described.

During this rolling action the flow of the metal is entirely circumferentially of the cup-shaped blank, there being substantially no flow longitudinally of the axis of the cup-shaped blank, that is. radially with reference to the finished disk, due to the fact that expansion produced by rolls is substantially entirely longitudinal (referring to the direction of movement of the part acted upon) and only slightly transverse or spreading, as is well known.

The result is a disk of the desired diameter in which the thickness varies uniformly and progressively from the circle forming the bottom of the cup-shaped blank to the periphery of said disk, and is such that the cross sectional area on any circle within this portion of the disk is exactly the same as that of any other circle within this portion of the disk; and producing such disk in a manner to avoid producing waves or irregularities in the metal, and also to prevent the formation of radial cracks, or strains tending to produce radial cracks.

I claim:

l. The method f making .disks hich consists in forming a metallic cup-shaped blank, rotatably supporting said blank by its bottom, and subjecting the same to a circumferential rolling action to reduce and expand the same, such reducing and expanding action being greatest at the open end of the cup and. decreasing toward its bottom,

thereby increasing the diameter of the cup in a uniformly increasing degree from the bottom of the cup to its open end and producing a disk of gradually decreasing thickness from its central portion to its [perimeter.

2. The method of making disks, which consists in forming a metallic cup-shaped blank, rotatably supporting said blank by ally decreasing thickness from its central portion to its perimeter.

3. The method of making disks, which consists in forming a metal disk into a deep substantially cylindrical seamless cup-shaped blank, and subjecting the walls of said blank to a circumferential rolling pressure to reduce and expand the same, said rolling action being greatest at the open end of the cup and decreasing toward its bottom, thereby increasing the diameter of the cup in a uniformly increasing degree from,its bottom to the open end and producing a disk of gradually decreasing thickness from its central portion to its perimeter.

4. The method of making disks, which consists in forming a metal disk into a deep substantially cylindrical seamless cup-shaped blank, and subjecting the walls of said blank to a circumferential rolling pressure, said rolling pressure being greatest at the open end of the cup and decreasing toward its bottom, and progressively increasing the rolling pressure at the open end of the cup as the rolling progresses, thereby increasing the diameter of the cup in a uniformly increasing degree from its bottom to its open end and producing a disk of gradually decreasing thickness from its central portion to its perimeter.

5. The method of making disks, which consists in forming a circular metal plate into a seamless cup, rotatably supporting said cup by its bottom, and subjecting the walls thereof to a circumferential rolling action to reduce and expand the same, such reducing and expanding action being greatest at the open end of the cup and decreasing toward its bottom, thereby increasing the diameter of the cup in a uniformly increasing degree from its bottom to its open end and producing a disk of gradually decreas- 1ng th1ckness from its central portion to its perlmeter.

6. The method of making disks, which conslsts in forming a circular metal plate into a seamless cup-shaped blank, rotatably supporting said blank by its bottom, and subjecting the walls thereof to a circumferentlal rolling action, said rolling action being greatest at the open end of the cup and decreasing toward its bottom, progressively increaslng the rolling pressure at the open end of the cup as the rolling progresses, thereby increasing the circumference of the cup in a uniformly increasing degree from its bottom to its open end and producing a disk of gradually decreasing thickness from its central portion to its perimeter.

7. The method of making disks, which consists in drawing a circular metal plate into a deep cylindrical seamless cup with walls of substantially uniform thickness, and then subjecting the walls of said cup to a circumferential rolling action to reduce and expand the same, said reducing and expanding action being greatest at the open end of the cup and decreasing toward its bottom, thereby increasing the diameter of the cup in a uniformly increasing degree from its bottom to its open end and producing a disk of gradually decreasing thickness from its central portion to its perimeter.

8. The method of making disks, which consists in drawing a circular metal plate 1nto a deep substantially cylindrical seamless cup, then subjecting the walls of said cup to a circumferential rolling action to reduce and expand the same, said reducing and expanding action being greatest at the open 'end of the cup and decreasing toward its bottom, and progressively increasing the rolling pressure at the open end of the cup as the rolling progresses, thereby increasing the diameter of the cup in a uniformly increasing ratio from its bottom to its open end and producing a disk of gradually decreasing thickness from its central portion to its perimeter.

In testimony whereof, I have hereunto set my hand.

ARNOLD CHRISTIANSO N.

Witnesses:

LYMAN H. FRAzmR, CHARLES H. RUPPEL. 

